Device for measuring the thickness and/or unevenness of wadding or non-wovens

ABSTRACT

The invention concerns a device for measuring the thickness and or unevenness of wadding or non-wovens. The device has a guide element ( 30 ) for the wadding or non-wovens and a thickness sensor ( 26, 27, 28 ) which presses the wadding or non-wovens against the guide element and can move relative to the latter, the position of the sensor providing a measure of the thickness and/or unevenness of the wadding or non-wovens. To achieve a simpler and cheaper design without sacrificing measurement accuracy, an individual sensor is provided with a translation element ( 31 ) which converts the deflections of the individual sensor in one direction into a path signal available in another direction. This allows signals corresponding to the deflections of several individual sensors to be added together and applied to a single common path measurement system ( 32 ).

FIELD OF THE INVENTION

The invention relates to a device for measuring the thickness and/ornon-uniformity of waddings or non-wovens, described hereinafter as“laps”, with a guide for the lap, with a thickness-sensing element whichpresses the said lap against the said guide and is movable relative tothe latter and the position of which represents a measure of thethickness and/or non-uniformity of the lap, and with a path measuringsystem.

BACKGROUND OF THE INVENTION

A device of this kind is already known from EP-A-0467117. In the saiddevice, the thickness-sensing element is formed by a plurality ofindividual sensing elements disposed side by side, which can beindividually shifted by the lap and extend over the breadth of thelatter. Disposed in each individual sensing element is an electricalmeasuring device for detecting the position of the individual sensingelement in relation to the guide. Signals for the position of eachindividual sensing element are thereby available which make it possibleto identify differences which exist in the thickness of the lap, viewedover the breadth of the latter.

SUMMARY OF THE INVENTION

A disadvantage of this known device consists in the fact that thedisposition of an electrical measuring device in each individual sensingelement is extravagant and costly. If the measuring device operates withexpansion-measuring strips, each individual measuring device has to becareful calibrated before starting, and this is an expensive process.

It is therefore an object of the present invention, such as ischaracterized in the patent claims, to provide a device of this kindwhich is simpler and cheaper, without it being necessary to acceptlosses in the quality of the measurements.

This is achieved through the fact that a thickness-sensing element isprovided with a transmission element which transmits the movement of thethickness-sensing element to the path-measuring system in a directionwhich does not coincide with the direction of movement of the thicknesssensing element. As a result of this, it is possible to provide apath-measuring system operating in a direction which can be selected atwill.

Apart from the simpler construction of a device of this kind, there isthe further advantage that the deflections of all the individual sensingelements are added at the same time, so that a signal is produced whichrepresents the average thickness of the lap. This signal thus no longerneeds to be ascertained by electrical processing of individual signals.The device can be designed in a simple manner for one, two or moreindividual sensing elements or even extended at a subsequent time to anumber of individual sensing elements. In addition, it is possible toprovide a path-measuring system operating in a direction which can beselected at will. When the device according to the invention is employedin a carder with an open regulating circuit, it is possible to supplythe latter direct with a value for the thickness of the lap which isaveraged over the breadth, a fact which permits more accurate regulationand leads to improved uniformity of the band at the outlet of thecarder.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in greater detail below with the aid ofexemplified embodiments and drawings. In the latter:

FIG. 1 shows a diagrammatic representation of a thickness sensingelement according to the invention, in a longitudinal section,

FIG. 2 shows a diagrammatic representation of a thickness sensingelement according to FIG. 1, in cross section;

FIG. 3 shows a diagrammatic representation of a thickness sensingelement with a number of measuring rolls, in longitudinal section,

FIGS. 4, 5 and 6 each show another embodiment of the device, in crosssection, and

FIG. 7 shows a diagrammatic representation of the device on a carder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a device according to the invention. In the figure, therecan be seen a lap 1 which rests on a fixed guide 2 and preferablyappears in the form of a loose fibrous structure such as, for example,wadding or a non-woven, which will hereinafter be described as a “lap”.A thickness-sensing element 3 is provided which rests on, or even sinksinto, the lap 1 and is constructed here, in particular, as a hollowmeasuring roll 3. The inner face 4 of the measuring roll 3′ has twoannular grooves 5, 6 which serve for the lateral guidance of pairs ofrollers 7, 8 which are supported on the measuring roll 3′. The pairs ofrollers 7, 8 have swivel pins 9, 10 which are mounted in a carriage 11.The said carriage has a support 12 which serves for mounting a reroutingroller 13 for a transmission element 14 which is to be flexible but asinelastic as possible and, in this case for example, is constructed as acable. Two other rerouting rollers 15, 16 are mounted on beam 17 whichprojects beyond end faces 18, 19 of measuring roll 3′ and in which oneend 20 of the transmission element 14 is fixedly mounted. The other end21 of the transmission element 14 is connected to a path-measuringsystem 22 and moves in the direction of an arrow 23 when the measuringroll 3′ is moved towards or away from the guide 2. The arrow 23 therebyindicates a direction which is inclined or bent in relation to adirection of movement of the thickness-sensing element 3 such as isindicated by an arrow 24. In addition to the actual measuring element 22a, the path-measuring system 22 also consists of a spring 22 b, anadjustable bearing 22 c for the spring 22 b on the beam 17 and acoupling element 22 d for the transmission element 14 which, this case,also serves as a measuring face for the actual oath-measuring element 22a. It can also be seen here, that a movement of the measuring roll 3′ inthe direction of the arrow 24 results, because of the formation of aloop in the transmission element 14, in twice as great an excursion ofthe end 21 in the region of the path-measuring system 22. It is therebyalso possible to achieve a doubling of the measuring accuracy. Thecontact pressure of the thickness-sensing element 3 against the guide 2is produced by the spring 22 b (in addition to the force of gravity).

FIG. 2 shows a cross section through the device shown in FIG. 1. It isagain possible to see therein the pair of rollers 7, 8, the carriage 11with the support 12 and the rerouting roller 13, and also the beam 17with a rerouting roller 15, 16 and a spindle 25 for the mounting thereofin the beam 17. As is apparent from FIGS. 1 and 2, the guide 2essentially forms a plane in this case.

FIG. 3 shows a device with three thickness-sensing elements 26, 27, 28which, in this case, are all mounted on a common beam 29 above a guide30. The construction of the thickness-sensing elements 26, 27, 23 isthat which is already known from FIGS. 1 and 2. In this instance, thethickness-sensing elements 26, 27, 28 all have a common transmissionelement 31 and a common measuring system 32 which is fastened on thebeam 29 on one side of the three thickness-sensing elements 26, 27, 28.The beam 29 may be connected, for example in a manner which is notrepresented in any greater detail here but is known, to the guide 30,may be supported thereon or may be mounted in some other way, inparticular in a stationary manner and at a fixed distance from theguide. In this case, the transmission element 31 traverses a number ofmeasuring rolls, which are disposed between the path-measuring system 32and a fixed mounting 51. A fixed mounting 32 c is also provided in thepath-measuring system 32 for a spring 32 b which is connected to thetransmission element 31 via a coupling element 32 d. The mounting 32 cis displaceable and adjustable along the beam 29, so that the tensioningforce of the spring 32 b and, with it, also the contact pressure of allthe thickness-sensing elements 26, 27, 28 provided, can be adjustedjointly.

FIG. 4 shows, once again, the use of a thickness-sensing element 3according to the invention above a stationary and flat guide 2 with alap 1 which is driven in the direction of an arrow 33 by means not shownhere, and thereby drives the measuring roll 3′. In the region of thethickness-sensing element 3, the lap 1 undergoes compression, so thatits height is reduced to an amount a.

FIG. 5 shows a thickness-sensing element 3, such as may be disposedabove a round guide, in this case a roll 34 which is driven in thedirection of an arrow 35. Here too, compression of the lap 1 to theamount a occurs.

FIG. 6 shows a thickness-sensing element-3 such as may be disposed abovea multipart guide, in this case consisting of two rolls 36 and 37 whichare driven in the direction of arrows 38. Here too, compression of thelap 1 to the amount a occurs.

FIG. 7 shows the application of a thickness-sensing element 39 accordingto the invention in the area surrounding a carder 40 with a can system41 connected downstream thereof for depositing carded band 42. Thecarder and the color can system have a common mechanical or electricaldrive 43 and a monitoring and regulating system 44. As is shown here,the thickness-sensing element 39 may be provided in the region of adraw-in roller 45 at the entry to the carder 40 and be connected to themonitoring and regulating system 44 via a line 46.

The way in which the device according to the invention works is asfollows: The measuring roll 3′ is lifted off from the guide 2 to agreater or lesser extent by the varying thickness of the-moving lap 1.In the process, a movement of the measuring roll 3′ is transmitted, viathe rollers 7, 8, the carriage 11, the support 12 and the reroutingroller 13, to the transmission element 14 which, under thesecircumstances, enlarges or diminishes a loop which it forms in theregion of the rerouting rollers 13, 15, 16. As a result of the movementof the transmission element, a transmitter in the path-measuring system22 is deflected to a greater or lesser extent, and this supplies theindication concerning the thickness or uniformity of the lap 1. Insteadof the transmitter 47, however, it is also possible for thepath-measuring system 22 to operate in a contact-less manner.

In the event of a number of such thickness-sensing elements 26, 27, 28being disposed side by side, the deflections of three loops 48, 49, 50are added up, so that there is produced, at that end of the transmissionelement which is fastened to the path-measuring system 32, a signalwhich corresponds to the averaged thickness of the lap 1. Since all theloops 48, 49, 50 start out from an average deflection, even in the caseof a zero thickness of the lap 1, very small thicknesses on onemeasuring roll are set off against larger thicknesses on anothermeasuring roll. In the case of a number of thickness-sensing elementsconnected in series, as is known from FIG. 3, the path-measuring system32 must also be calibrated in a corresponding manner.

What is claimed is:
 1. Apparatus for measuring the thickness ornonuniformity of waddings or non-wovens, described hereinafter as laps,said apparatus comprising a guide for the lap being measured, athickness-sensing element which presses said lap against said guide andis movable relative to said guide so that the position of said thicknesssensing element represents a measure of the thickness or non-uniformityof the lap, a measuring system, and an elongated flexible transmissionelement extending along a path having multiple directions, saidtransmission element being constructed and disposed for the transmissionof the movement of the thickness-sensing element to the measuring systemin a direction which is at a desired inclination relative to thedirection of movement of the thickness-sensing element.
 2. Apparatusaccording to claim 1, wherein said flexible transmission element isrerouted around rollers and is fixedly mounted at one end and connectedto the measuring system at the other end.
 3. Apparatus according toclaim 1, wherein the thickness-sensing element comprises a measuringroll which is mounted movably and rotatably on a beam which is at afixed distance from the guide.
 4. Apparatus according to claim 3,wherein the measuring roll is hollow, the beam traverses the saidmeasuring roll and, at the same time, projects beyond at least one endface (18, 19) of the said measuring roll.
 5. Apparatus according toclaim 1, including a number of thickness-sensing elements disposed sideby side, and wherein said transmission element extends over a number ofsaid thickness-sensing elements.
 6. Apparatus according to claim 5,wherein said transmission element transmits the movements of said numberof thickness-sensing elements to said measuring system.
 7. Apparatusaccording to claim 2, wherein said transmission element is disposed soas to traverse a number of measuring rolls which are provided betweenthe measuring system and the fixedly mounted end of said transmissionelement.
 8. Apparatus according to claim 2, wherein said transmissionelement forms a loop at the thickness-sensing element, so that the pathof the deflections of the thickness-sensing element is doubled fordetection in the measuring system.
 9. Apparatus according to claim 2,wherein the transmission element is connected, in the region of themeasuring system, to a spring which is adjustable to exert an adjustableforce for pressing the thickness-sensing element toward said guide. 10.Apparatus according to claim 9, wherein adjustment of a single springadjusts the pressing force of a number of thickness-sensing elements.